The present invention relates to water treatment systems; more particularly, the present invention relates to systems which make environmentally suitable water from water which has been contaminated with hydrocarbons and other substances.
In many situations, typically involved with the production, refining, transportation or storage of hydrocarbon products, there is the possibility of contaminating local groundwater with tank-cleaning runoff, spillage or leaks. In such situations, it may become necessary to process or purify contaminated local groundwater to return it to an environmentally suitable state.
While numerous systems for treating contaminated water have been proposed, no one treatment system has been effective to consistently and economically transform contaminated water to an environmentally suitable state.
Examples of prior art water treatment systems may be found in the following U.S. Patents:
U.S. Pat. No. 2,730,190 to Brown et al. relates to the treatment of water which contains oil. Herein, a combination oil washing and gas flotation process is used for the removal and recovery of oil and solids from streams of water. The contaminated stream of water is first subjected to an optional gas removing step. The treated water-is then contacted with a stream of finely dispersed gas bubbles produced by means of a jet flotation device.
In U.S. Pat. No. 2,766,203 to Brown et al., a water purification process and apparatus is disclosed. Herein, a multi-zoned floatation system is used for the treatment of oil-contaminated water streams.
U.S. Pat. No. 3,565,252 to Sheehy et al. discloses a system for the processing of fluids used to wash oil tanks in ocean-going vessels.
In U.S. Pat. No. 5,227,071 to Torline et al., a five-stage treatment system for treating oily wastewater is disclosed. Herein, a coalescer is used for separating free oil, an ultrafiltration unit is used for separating emulsified oil, an activated carbon filter is used for separating residual light organic compounds, a Cat-ion exchanger is used for removing heavy metal ions, a pH adjusting unit is used for adjusting the pH of the treated water, and a controller is used for regulating the operation of the entire system.
U.S. Pat. No. 4,139,463 to Murphy et al. relates only to an oil-and-water separation system.
In U.S. Pat. No. 5,302,294 to Schubert et al., a separator system employing degassing separators and hydrocyclones is disclosed. The invention is directed to the use of a hydrocyclone at an early stage in the separation process. The hydrocyclone separator is then used in conjunction with an initial gravity separator, or in some instances, the hydrocyclone separator is employed as the first separator.
While the foregoing systems teach the removal of contaminants from water, each has its limitations with regard to producing environmentally suitable water. Therefore, the need remains in the art for a treatment system which will consistently and economically transform contaminated water into an environmentally suitable state.